Question

Which of the following key does not allows to add duplicate records?

a) Primary key b) Foreign key c) None of these​

Answer 1

$\huge\fbox \red{A}\fbox \green{N}\fbox \purple{S}\fbox \orange{W}\fbox \red{E}\fbox \blue{R}$

Foreign key.

$\sf{ \blue{ɧơ℘ɛ  \:  ɬɧıʂ \:    ɧɛƖ℘ʂ \:   ყơų}}$

Answer 2

Answer:

$\huge \tt \color{blue}{primary \: key}$

The error clearly says that this statement violates the primary key constraint and that duplicate values cannot be inserted into the primary key column. Since both primary key and unique columns do not accept duplicate values, they can be used for uniquely identifying a record in the table.